1. EXCERPTS from BASIC FIREARMS IDENTIFICATION
Lucien C. Haag
Criminalist
Forensic Science Services, Inc.
Carefree, AZ 85377
Prepared for DCA Vince Imbordino

2. PRINCIPLES OF FIREARMS IDENTIFICATION
CALIBER DESIGNATIONS
Caliber relates to the nominal inside dimensions of the barrel

3. PRINCIPLES OF FIREARMS IDENTIFICATION FOUR COMMON RIFLING ARRANGEMENTSRt Rt Rt Lt
Direction of Rotation

4. PRINCIPLES OF FIREARMS IDENTIFICATION:
Class Characteristics Imparted to Fired Bullets
RIGHT TWIST
LEFT TWIST

5. Examples of Fired Bullets
Right Twist Left Twist

6. SLIDE SOURCES of MARKS on CARTRIDGE CASES BREECHFACE FIRING PIN
EXTRACTOR
EJECTOR

7. breechface extractor SLIDE removed from a Semi-Automatic Pistol
Support Area
for the
Cartridge
extractor
SLIDE
removed
from a
Semi-Automatic
Pistol

8. Live Cartridge loaded from the Magazine
Slide retracted
extractor
ejector

9. EJECTOR MARK on an Extracted and Ejected Cartridge Case
ejector mark firing pin impression
ejector
Impact site
Typical ejectors are located
at the 7 to 8 o’clock position

10. barrel slide CARTRIDGE CASE EJECTION from a SEMI-AUTOMATIC PISTOL
Ejector
slide

11. STYLIZED BREECHFACES
with
VARIOUS TOOL MARKS
FIRED CARTRIDGES

12. VARIOUS EJECTOR SHAPES
STYLIZED BREECHFACES
and
VARIOUS EJECTOR SHAPES
FIRED CARTRIDGES
with
EJECTOR MARKS

13. Summary of Markings on
Cartridge Cases

14. BASIC FIREARM and TOOLMARK IDENTIFICATION
-end-
Lucien C. Haag
Criminalist
Forensic Science Services, Inc.
P.O. Box 5347
Carefree, AZ 85377